Business forms with pressure activated adhesive or cohesive have become increasingly popular because of numerous practical advantages associated therewith. These adhesives (such as sold by Toppan Forms Company of Japan with a trade designation TN124, and as disclosed in U.S. Pat. Nos. 4,918,128, 5,190,818, 5,314,944 and 5,427,851) require application of a substantial force in order to effect sealing. A wide variety of different pieces of pressure seal equipment have been developed for that purpose, such as sold by Moore U.S.A., Inc. of Lake Forest, Ill. under the trademark "SpeediSealer", and such as shown in U.S. Pat. Nos. 5,169,489, 5,378,303, 5,397,427 and 5,527,416 (the disclosures of which are hereby incorporated by reference herein). While this commercial equipment is very useful in effecting proper sealing and handling of business forms with pressure activated adhesive or cohesive, it would be desirable to reduce the weight of the equipment, reduce its foot print, and provide a lower cost to the end user.
According to the present invention a method of handling business forms with pressure activated adhesive or cohesive thereon, and sealing apparatus that can be utilized with such business forms (or with other webs or sheets) is provided which has a number of advantages over conventional methods and equipment under some circumstances. The equipment provided according to the invention can have reduced weight, a reduced foot print, and a lower cost to the end user than equipment such as described above since the number of rollers utilized to effect the sealing action is reduced, and they can be positioned in such a way as to have a small foot print. Despite reduced weight, foot print, and cost, the equipment according to the invention can substantially effectively seal business forms as conventional equipment for that purpose.
According to one aspect of the present invention a method of handling business forms with pressure activated adhesive or cohesive thereon using at least first, second and third rollers each having an axis of rotation, and the axes of rotation being vertically spaced from each other so that the second roller axis is at a vertical location intermediate the first and third roller axes, and a first nip is formed between the first and second rollers and a second nip is formed between the second and third rollers is provided. The method comprises: (a) Feeding a business form with pressure activated adhesive or cohesive thereon into and through the first nip to effect compression. (b) Changing the direction of movement of the business form to direct the business form toward the second nip. And (c) feeding the business form into and through the second nip to effect sealing of the pressure activated adhesive or cohesive on that part of the business form between the rollers.
Typically (c) is practiced to apply a force to the business form between the second and third rollers of between about 100-200 lineal pounds per inch, and (a) is practiced to also apply the same general level of force, e.g. between about 100-200 pounds per lineal inch. (a) and (c) are also preferably practiced to operate on two different forms at the same time, that is one form goes through the first nip while a second form is passing through the second nip. This maximizes the pressure in both the compression and sealing phases (that is between the first and second nips).
(b) may be practiced by feeding the business form into contact with a substantially semicircular stationary surface, or by using a plurality of sets of re-directing rollers, with or without stationary guides associated with them. Any other conventional equipment can also be used which effectively allows re-direction of a form once passing through the first nip to the second nip.
The business forms may be constructed to have pressure activated cohesive or adhesive in strips along two peripheral portions thereof, and (a) and (c) may be practiced (using rollers designed for that purpose) to act substantially only on the peripheral portions of the form. This is particularly useful when the form is to have inserts and it is desired not to "crush" the inserts. Alternatively, however, especially where inserts are not used in the form, and the form has a width substantially transverse to the primary direction that it moves through the nips, (a) and (c) are practiced to act along substantially the entire width of the business form. In such a case typically the form has at least some pressure activated adhesive or cohesive extending substantially parallel to the width thereof, and the rollers seal the form both where there are longitudinal and transverse strips of adhesive or cohesive.
In the practice of the method, the roller axes may be substantially vertically aligned so as to provide a minimum foot print, when (a) through (c) are practiced, and (a)-(c) are typically also practiced by driving each of the first, second and third rollers.
According to another aspect of the present invention sealing apparatus is provided, which is utilizable with the business forms as described above, or perhaps also utilizable for other webs or sheets. Sealing apparatus comprises the following components: A plurality of rollers, including at least first, second, and third rollers, each having an axis of rotation, and the axes of rotation being substantially vertically aligned with each other and the second roller axis provided at a vertical location intermediate the first and third roller axes. A first nip formed between the first and second rollers, and a second nip formed between the second and third rollers. And means for changing the direction of movement of a web or sheet passing through the first nip to direct the web or sheet toward the second nip, while the web or sheet is spaced from the second roller when moving between nips.
In the sealing apparatus according to the invention preferably all three (or more) of the rollers are driven. For example, the second roller is operatively connected to a motor and the first and third rollers are geared to the second roller. The plurality of rollers may consist of the first, second and third rollers. The means for changing the direction of movement of a web or sheet passing through the first nip to direct the web or sheet toward the second nip may comprise a substantially semicircular stationary surface, or a plurality of sets of re-directing rollers with or without associated stationary guides. However, any other conventional or to be developed structure may be used that performs the function of changing the direction of movement of the web or sheet (business form) to direct the web or sheet from the first nip toward the second nip, though the web or sheet is spaced from the second roller when moving between the nips.
The rollers may be positioned and constructed so that the second and third rollers apply a force of at least about 100 pounds per lineal inch, and preferably between about 100-200 pounds per lineal inch therebetween. Similarly, the rollers are preferably positioned and constructed so that the first and second rollers apply a force of between about 100-200 pounds per lineal inch.
The rollers may have a diameter of about 2-4 inches in most circumstances, and can either have a short axial length (5inches or less) to act merely along one edge of the business form or other web or sheet, or segmented rollers can be provided on a shaft which are spaced from each other to act on separate longitudinal edges of the business form, or other web or sheet, passing between them. Alternatively, a continuous roller extending across the entire width of a web or sheet (e.g. business form) to be acted upon may be provided. The rollers can be made of any suitable materials or have any suitable configuration, for example, such as shown in U.S. Pat. Nos. 5,169,489, 5,378,303, 5,397,427 and 5,527,416.
It is the primary object of the present invention to provide a sealing apparatus which has a reduced weight, reduced foot print, and lower cost to the end user, than conventional equipment for sealing business forms having pressure activated adhesive or cohesive thereon, and a method of acting on business forms using such equipment. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.